Ejector type welding electrode holder



Feb. 8, 1949. E. 1. LARsEN EJECTOR TYPE WELDING ELECTRODE HOLDER Filed Mayl 28, 1946 INVENT OR. fdr] I aM/f@ ,f/daa@ W NNWM Patented Feb. 8, 19149 EJECTOR TYPE WELDING ELECTRODE HOLDER Earl I. Larsen, Indianapolis, Ind., assigner to P. R.

Mallory & Co., Inc., Indianapolis, Ind., a corporation of Delaware Application May 28, 1946, Serial No. 672,857

7 Claims.- l

This invention relates to Welding electrode holders for resistance Welding.

This invention further relates t welding electrode holders in which the Welding electrode is adapted to be ejected from the holder.

In resistance Welding machines, the -electrodes are ordinarily supported by an electrode holder which supplies cooling fluid to the inside of the electrode as the Welding operation proceeds. It is customary to provide the electrode holder with a tapered socket in which the Welding electrode or tip fits and the holder is usually provided with a cooling iiuid conduit which extends into a recessed portion of the electrode to supply it with cooling uid. It is oftentimes necessary to remove or replace the welding electrodes, due to Wear or deformation,'and different types of Work require the substitution of different electrodes. The electrode tip should lit quite yclosely and tightly into the socket in order to assure good electrical conductivity and mechanical support as Well as to prevent leakage of the cooling fluid. When removing such an electrode tip from a holder which is not provided with an ejector device, the Welding electrode must be twisted with a pair of pliers, a pipe Wrench or similar tool until it has loosened suflcientlyl to permit removal thereof from the holder.

The obvious difliculties of this method Iof removal were overcome, in part, by the ejector-type Welding electrode holder such, for example, as the holder described in Hensel and Larsen Patent No. 2,215,289. In this patent, an ejector tube is disposed inside the barrel or body of the electrode holder and this tube extends from thefwelding electrode to a stuffing box or packing gland at the rear of the holder. The tube may. have cooling fluid inlet and outlet fixtures attached thereto for supplying cooling fluid to the Welding electrode. When the electrodeis to be removed, the tube is struck a blow with a hammer or mallet thus forcing the tube against the electrode and loosening the latter from the tapered socket.

Difficulties have arisen in the use of this type of electrode holder in that it is very diiiicult to provide a stuffing box or packing gland which remains water tight for a long period of time. Accordingly, frequent repacking or adjustment of the Stuiing box is necessary in order to insure proper functioning of the electrodeholder.

In accordance with this invention, the stuffing box and its attendant disadvantages is altogether eliminated by the use of an internal piston which is operated by uid pressure, such piston being adapted to engage the ejectortube .to force it.,

against the Welding tip, thus loosening the tip from the holder. The piston may be readily sealed without the use of a stufling box or packing gland so that water leakage is effectively prevented. In addition, the novel construction of the electrode holder is such that the cooling fluid is automatically turned olf both at the inlet and outlet when the welding tip is removed, thus preventing leakage or spilling of the cooling fluid. The piston may be operated by any suitable source of fluid pressure so that it is not necessary to strike the ejector tube with a mallet or hammer when it is desired to remove the welding electrode.

It is an object of this invention to provide a welding electrode holder in which the welding tip may be ejected by the application of fluid pressure.v It is a further object of the invention to provide a Welding electrode holder in which leakage or spilling of cooling fluid is eliminated or greatly minimized.

It is a still further object of the invention to provide a welding electrode holder which is of rugged construction, reliable in operation, and which may be manufactured at a low cost.

Other objects of the invention will be apparent from the following description and accompanying drawings taken in connection with the appended claims.

The invention accordingly comprises the features of construction, combination of elements, arrangement of parts, and methods of manufacture referred to above or which will be brought out and exemplified in the disclosure hereinafter set forth, including the illustrations in the drawings, the scope of the invention being indicated in the appended claims. Y

For a fuller understanding of the nature and objects of the invention as Well as for specific fulfillment thereof, reference should be had to the following detailed description taken in connection With the accompanying drawings, Y in which:

Y Figure 1 is a vertical sectional view of a welding electrode holder construction in accordance with the present invention;

Figures 2 and 3 are, respectively, sectional views taken along the lines 2 2 and 3 3 of Figure 1.

While avpreferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the construction of parts without departing from the spirit of the invention. In theA following description and in the claims, parts Will be identified by specific names for convenience, but they are intended to be as generic ofthe passage H.

in their application to similar parts as the art will permit.

Referring now to the drawings in detail and particularly to Figure l, a barrel type welding electrode holder is shown comprising a hollow body I through which extends a longitudinal passage |I'. One end of the passage: I|l is tapered as at I2 to receive a welding electrode or'tip i3' Vhaving a cooling fluid recess I4 therein. The body portion or barrel I0 is adapted to be clamped in an arm of a suitable resistance welding machine.

An `ejector member or tube |"5 is' disposed. within the passage I'I and said tube is adapted to move longitudinally of the body |50' into engage'- ment with the end I5 of the welding electrode. The other end of the tube I5 extends into an enlarged portion I1 of the passageV |20 and is provided with a flange I8 which is adapted to nt against the walls of the passage. The flanged portion I8 is adapted to be engaged by one end t9? of a piston'- Zwhich. is movable longitudinally The other end of thea piston extends into. al recess 2|' formedl inthe4 body I0 and this endv of the" piston is flanged as at 22 for engagement with the walls of' the chamber. washer' 23 or leath'en. rubber or other suitable material is secured to the flanged'. endof the piston. by a screw 2.4' and-fa. metallic washer .25, saidi washer 23?l serving to divide. the recess 21|: into a pressurechamber-ZG. and a pistonchamber 271:'.V The pressure'chamber 2.6 is: partially de'- fined by a cap 2.8:' whichis screwethreaded tothey interior` of the passage and'. sealed' by a suitable washer 29.

VFluid.' under pressure may be admitted toy the chamber-.2E by a nipple 31|, which: is screwthreaded onV the cap 28,. and .a hose 3|. When huid:y under pressure isadmittedv to chamber 26,.

the piston 201 is forced. inwardly into. engagement with therejector tube I5 which, in: turn, engages' the welding electrode |13vv toithereby force or loosen itfrom the socket` |22 is removed from the chamber 2E, thepiston is returned toits original positionV by a compression spring 32 which is mounted|` in the chamber 2l.Y I prefer to--utilize compressed air as the uid' for operating thepiston as compressed' air is readily available at most places Where resistance welding machines are used. In order that the air pressure; shall not become unduly high in the chain` ber '.21'- as the piston moves inwardly, avent 33 is provided' so that the interior of chamber 21 is maintained at substantially atmospheric pressurein any positionA of the piston 20a' The water cooling system for the electrode holder comprises an inlet 35y and anoutlet 3B' whichv are formed in the bod-y or barrel IU- and are'suitably threaded to receive-a Iwater inlet and' outlet valve, respectively;H With the piston ing tip by a compression spring 42 which is ser' cured, at onev endthereof, to aY-collarVv l|3y formed in the conduit 4G and, at the other end thereof, to' the conduit 4I. VWhen. the welding machine is operated, cooling'uid passes through the inlet 35, lconduit V41|,V and'cond-uit 4|I` to the recessed- When the fluid pressure portion I4 of the tip. Thence, the cooling fluid passes to the outlet 35 through the interspace 44 between conduit 4U and ejector tube I5. It will be noted that the tube i5 is provided with suitable passages 45 through which the cooling fluid.

through nipple 3l! into pressure chamber 26, the

piston moves inwardly thus forcing the ejector tube |25A into engagement with the tip and ejecting the same from the socket l2. It will be understood a suitable air line may be connected to the nipple 3|! for the purpose of applying fluid pressure: tothe chamber 26; This air line should preferably be provided with a` suitable valve for successively applying pressure to the chamber in case Ithel rst pressure. application. fails to.- loosen the tip sufficientlyl to. allow removal thereof or in case it is necessary that the welding electrode be frequently replaced. At the same time, the annular -groove 38 moves. out of register with the inlet35. so that the supply of cooling hui-d to the electrode holder isW cut off. Furthermore, as the ejector tube |-5- moves intoL engagement with the tip, the passages 45 are no longer in register with the outlet' 36 whereby the cooling fluid outlet is also closed.- When the huid pressure is removed from the chamber 26, the spring 32 forces the piston outwardly toits original position so thatv the annulus 38 registers with inlet 35 and the passages 45 arev inregister with the outlet 35. Thereupon, the flow of cooling fluid through the electrode holder i's resumed.

It will be apparent that the novel electrode holder of the present invention obviates the necessity of providing a stuffing box or packing gland` for the'ejector tube and that the construction-` of the novel electrode holder is simple and economical. When the tip is ejected, the supply of cooling uid is shut off so that the inconvenience of having the uidescape from the electrode holder while the tip is being changed is positively eliminated. A

Thetip is ejected solely by the fluid pressure applied tothe chamber 26 thus eliminating the vnecessity of striking the ejector tube with a mallet or hammer; The use of huid pressure for-this purposeV affords smoother operation and avoids much of the. wear previously caused by striking: the tube with a tool in order to eject the tip..

While the present invention, as to its objects and advantages, has been described herein as carried out in specific embodiments thereof, it is not desired to be limited thereby but it isl intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. An ejector type welding electrode yholder comprising a hollow body, a socket therein for receiving a welding electrode, an ejector member adapted to move into engagement with said elecm trodeto eject it from the socket, a piston disposed in said body and adapted to engage said ejector member, a cooling fluid inlet and a cooling fluid outlet, means for delivering cooling fluid from :the inlet to the welding electrode and then res. turning the cooling fluid to said outlet, and means for applying fluid pressure to said piston to force it into engagement with said member to thereby eject said welding electrode, said piston and said member being constructed and arranged" to close said cooling fluid inlet and said cooling fluid outlet when moved to said electrode ej ecting position.

2. An ejector type welding electrode holder comprising a hollow body, a socket therein for receiving a welding electrode, ejector means including a member adapted to move into engagement with said electrode to eject it from the socket and a piston adapted to engage said ejector member, a cooling fluid inlet and a cooling fluid outlet, said ejector means having openings formed therein communicating with said inlet and said outlet in one position of said piston means for delivering cooling fluid from the inlet through one of said openings to the welding electrode and returning the cooling fluid through another of said openings to the outlet, means for applying fluid pressure to said piston to force it into engagement with said member to thereby eject said welding electrode, said movement of the piston also being effective to close said cooling fluid inlet and said cooling fluid outlet, and means for retracting said piston after the fluid pressure has been removed therefrom, the retraction of said piston being effective to open said cooling fluid inlet and said cooling uid outlet.

3. In an ejector type welding electrode holder, a body including a longitudinally-extending passage, a socket for receiving a welding electrode at one end of said passage, an ejector tube disposed in said passage and adapted to engage said electrode, a piston mounted in an enlarged portion of said passage for engagement with said ejector tube, said piston having an inner recessed portion which normally communicates with a cooling fluid inlet provided in said body, a conduit secured to said piston and communicating withv said recessed portion, said conduit extending through said passsage to supply cooling fluid to said welding electrode, the interspace between said conduit and said ejector tube normally communicating with a cooling fluid outlet formed in said body, a pressure chamber associated with said piston, and means for applying fluid pressure to said chamber to force the piston into engagement with said ejector tube and thereby eject said welding electrode, the movement of said piston also being effective to move said recessed portion out of communication with said inlet thereby to close said cooling fluid inlet.

4. In an ejector type welding electrode holder, a hollow body, a socket therein for receiving a welding electrode, an ejector tube disposed in said hollov.7 body and adapted to bear against said welding electrode, a piston disposed in said body for engagement with said tube, a cooling fluid conduit mounted inside said tube and se cured to said piston, said conduit consisting of inner and outer telescopic sections, means for urging the inner section into engagement with the welding electrode, a cooling fluid inlet and a cooling fluid outlet formed in said tube, means including an opening formed in said piston for establishing communication between said cooling fluid inlet and the interior of said conduit; means for establishing communication between said outlet and the interspace between said tube and said conduit, means for applying fluid pressure to said piston to force it into engagement with said ejector tube and thereby eject said welding electrode, said movement of the' piston also' being l effective to close said opening and said coolingi fluid inlet, and means to return said piston to its original-'position after the fluid pressure has ,been removed, thev return of said piston being effective' to open said cooling fluid inlet.

5. In an ejector type welding electrode holder, a body including a longitudinally-extending pas-- sage, a socket for receiving a welding electrode formed at one end of said passage, an ejector tube disposed in said passage and adapted to engage said electrode, a piston mounted in an enlarged portion of said passage for engagement with said ejector tube, said piston having an inner recessed portion which normally communicates with a cooling fluid inlet formed in said body, a conduit secured to said piston and communicating with said inner recessed portion, said conduit extending through said passage to supply cooling fluid to said welding electrode, the interspace between said conduit and said ejector tube normally communicating through said tube with a cooling fluid outlet formed in said body, a pressure chamber for said piston, means for applying fluid pressure to said chamber to force the piston into engagement with said ejector tube and thereby eject said welding electrode, the movement of said piston also being effective to move said recessed portion out of communication with said inlet and to interpose a portion of said tube between said interspace and said outlet thereby to close said cooling fluid inlet and said cooling fluid outlet, and means for retracting said piston after the fluid pressure has been removed therefrom, the retraction of said piston also being effective to open said cooling fluid inlet and said cooling uid outlet.

6. In an ejector type welding electrode holder, a hollow body, a socket therein for receiving a welding electrode, an ejector tube disposed in said hollow body and adapted to bear against said welding electrode, a piston disposed in said body for engagement with said tube, a cooling fluid conduit mounted inside said tube and secured to said piston, said conduit consisting of inner and outer telescopic sections, means for urging the inner section into engagement with the welding electrode, a cooling fluid inlet and a cooling fluid outlet formed in said tube, means for establishing communication between said cooling fluid inlet and the interior of said conduit, means for establishing communication between said outlet and the interspace between said tube and said conduit, means for fluid applying pressure to said piston to force it into engagement with said ejector tube and thereby eject said welding electrode, said piston and said member being constructed and arranged to close said cooling fluid inlet and said cooling fluid outlet upon such movement of the piston, means for sealing said piston and said hollow body between said inlet and said outlet, and means for sealing said pistonv and said body at a position between the inlet and the adjacent end of the electrode holder.

7. An ejector type welding electrode holder comprising a hollow body, a socket therein for receiving a welding electrode, ejector means including a member adapted to move into engagement with said electrode to eject it from the socket and a plunger adapted for engagement with said member, a cooling fluid inlet and a cooling fluid outlet, said ejector means having an opening formed therein communicating with said inlet in one position of said plunger, and

mmm

23858 SBEOTy Sept. 1.8, 1945 REFERENCES CITED Y folbw-i-ngf :references aire of recordf in theA m 'f Gf 5h18? patenti' 

